Movement transmission system for silk-screen



L. G. DUBUIT March 31, 1964 3,126,824 MOVEMENT TRANSMISSION SYSTEM FOR SILK-SCREEN PRINTING MACHINES AND THE LIKE 3 Sheets-Sheet 1 Filed Oct. 30, 1962 Inventor:

G. DUBUlT 3,126,824 MOVEMENT TRANSMISSION SYSTEM FOR SILK-SCREEN March 31, 1964 PRINTING MACHINES AND THE LIKE s Sheets-Sh eet 2 Filed Oct. 30, 1962 w W m n 0 Q. I m & m A a E I: I i w a I I: [i g Q i 1 i u t t i I M W Q II I ii. W |I I; m i w 3 I $3 I i Q. E \\-N\\ I Q 1H LY W\ k\ l r 1H1 I J N n v k M. N x r March 31, 1964 L. G. DUBUIT 3,126,824

MOVEMENT TRANSMISSION SYSTEM FOR SILK-SCREEN PRINTING MACHINES AND THE LIKE Filed Oct. 50, 1962 v s sheets-sheet a Inventor:

LOUIS GIL DUBUIT Attorne United States Patent Ofiice 3,126,824 Patented Mar. 31, 1964 3,126,824 MOVED HINT TRANSMISSION SYSTEM FOR SILK- SCREEN PRINTING MACHINES AND THE LIKE Louis Gilbert Dubuit, 60 Rue Vitruve, Paris, France Filed Oct. 30, 1962, Ser. No. 234,200 Claims priority, application France June 1, 1962 3 Claims. (Cl. 101-124) This invention relates to movement transmission systems as applied to printing machines, particularly though not exclusively to printing machines of the type employed in the so-called silk-screen printing process, and of related types.

In the so-termed silk screen printing process, there is generally provided a pattern screen member which is partly permeable to printing fluid or ink, and a fluid transfer member-(or squeegee) engageable therewith. Means are provided for reciprocating one of said members relative to a surface of an article to be printed on with the screen in engagement with said surface and the squeegee in engagement with the screen for transferring the printing fluid by the squeegee through the screen to said surface, thereby to impress a desired pattern upon the latter. More specifically, in cases where the work is an article of generally circular 'cross sectional contour, such as a cylindrical or conical (or other similar) object, upon the peripheral surface of which the pattern is to be printed, the object is supported for rotation about its geometrical axis and the pattern screen member reciprocated relative to the article while in tangential engagement with the surface thereof along a generatrix of said surface, while the article is allowed to revolve, or positively rotated, about its axis in synchronism with the displacement of the screen, thereby to impress the pattern over all, or a substantial part, of the developed peripheral surface of the article. The squeegee member is then usually positioned substantially stationa-rily above the screen along the contact generatrix of the screen with the work surface.

The circumferential extent of the print pattern that can be impressed by means of such a machine of given size is clearly determined by the maximum amplitude of reciprocation that can be imparted to the pattern screen. Hence, if it is desired that the printed pattern shall encompass say the full circumference of the work article, or a given fraction thereof such as one half the circumference for instance, it is clear that the machine will only be capable of handling work objects the circumferential size of which is not greater than a given size corresponding to the maximum reciprocatory displacement impartable to the screen of the machine under consideration. In conventional printing machines of this character, there is usually provided a carriage reciprocable on rails, and the pattern screen is supported for bodily displacement with said carriage. Hence, the maximum size of the work articles that such a machine will usefully accept is strictly limited at the construction of the machine by the maximum amount of reciprocation that can be imparted to the carriage thereof.

It is an object of this invention to eliminate this limitation and to provide simple, efficient, and convenient means whereby a machne of the type described can be effectively used in conjunction with work objects of a size considerably greater, e.g. two or more times greater, than the maximum nominal size for which the machine was originally designed, thereby eliminating the necessity for purchasing an expensive new machine in many instances.

It is an object to provide such means which may be in the form of an attachment fittable to an existent machine, or may if preferred be directly incorporated to a machine during the construction of it.

Another object of the invention is to provide improved movement transmitting means between a reciprocating carriage of a printing machine and a reciprooable printing member of said machine, whereby the amplitude of reciprocatory movement may be considerably amplified.

The invention is especially useful as an improvement in silk-screen printing machines of the general type disclosed e.g. in US. patent application Serial No. 102,331, filed February 15, 196 1, now Patent No. 3,090,300, and assigned to the present assignees.

Briefly, according to an important aspect of the invention, there is provided in a pattern-printing machine having a printing member reciprocable relative to a printing surface for transferring a print pattern to said surface, a reciprocable carriage, and a pulley-block movement transmission system interposed bet-ween and connected to said carriage and said reciprocable member, for transmitting movement from said carriage to said member, with a movement-amplification factor greater than unity.

in its simplest form, the pulley-block movement transmission system may comprise a pulley rotatably mounted on the carriage, and a wire having one end attached to a stationary point and another end attached to said reciprocable member and trained around said pulley, Preferably however, there is provided at least one pair of pulleys rotatably mounted on the carriage near opposite ends of it and a pair of wires each having an end attached to a stationary point and another end attached to the reciprocable member and trained about a related one of said pair of pulleys so as to transmit movement of the carriage in either of two opposite directions as an amplified movement of said one member in a corresponding direction.

In this simple form the amplification factor provided by the pulley block transmission system is substantially equal to two. It is, however, among the objects of the invention to provide similar systems wherein the amplification factor may be greater than two, through the use of more complex pulley-block systems involving more than one pulley around which the, or each, wire is suitably trained as well-known in the art.

Exemplary embodiments of the invention will now be described for purposes of illustration but not of limitation with reference to the accompanying drawings, wherein:

FIG. 1 is a simplified side view of the parts essential to the invention in a silt-screen printing machine equipped with the improved motion transmitting system for printing on cylindrical Work surfaces;

FIG. 2 is a corresponding plan View;

FIG. 3 is a view similar to H6. 1 relating to a modification of the invention as applied to a silk-screen printing machine for printing on conical work surfaces; and

FIG. 4 is a corresponding plan View.

Referring to FIGS. '1 and 2, a silk-screen printing assembly according to the invention comprises a carriage constructed, as shown, generally in the form of a pair of parallel spaced longitudinal members l having a pair of arms l secured thereto at their opposite ends, which arms are apertured and are freely slidable along a pair of parallel horizontal rails '2 and 2'. The rails 2, 2 are carried at the ends of parallel links 21, 122 pivoted on shafts 23 and 24 to uprights such as 25 forming part of the fixed frame of the machine, the pivot shafts 23 and 24 being disposed in relation to the rails 2, 2 so as to form there/with a parallel-linkage structure including links 21, 22 and arms 1'.

Secured to the longitudinal carriage emembers 1, preferably toward the ends thereof and immediately inward of the arms 1, is a pair of cross members 3 from each of which projects a pair of generally horizontal vertically spaced arms 4 and 4 provided with end spigots 5 upon which grooved pulleys or rollers 7 and 7' respectively are mounted by way of suitable ball or the like bearings 6 and 6.

A straight bar or guide rail 8, such as a fiat sectional element, is arranged between the two respective pairs of rollers 7 and 7 with its upper and lower horizontal edges engaging the grooves in the rollers so as to be freely reciproca-ble relative to the carriage 1 in the same longitudinal direction as that of the reciprocation of the carriage 1 relative to the frame. Secured to the bar 8 near its opposite ends, and projecting therefrom horizontally is a pair of supporting arms 9' and 9' which serve to support a conventional silk screen frame assembly shown in broken outline at 10 and not further described since it may comprise any suitable assembly well known in the art.

As shown in FIGS. 1 and 2, the parallel links 21 and 22 are extended beyond the rails 2 and 2 and the extensions have a link 20 pivoted thereto, so as to participate in the parallel displacements of said rails in the operation of the assembly as later described. Projecting forwardly from link 29 is a support 16 carrying an arm or rail 17 upon which a conventional squeegee carrier member 18 is slidably mounted.

Secured to the ends of the carriage members 1 beyond the arms 1 is a further pair of horizontally projecting arms or brackets 11, 11' each of which supports a vertical pivot 12, 12' on which a grooved pulley 13, 13' is rotatably mounted. A first flexible element or tow-line 14, e.g. a wire, has one end or second branch fastened to one end point 19 of the bar 8, said wire 14 extending around the groove in pulley 13 and having its other end or first branch fastened at 15 to a point of the squeegee supporting member 16. A second flexible element or tow-line 14, e.g. another wire, similarly has one end fastened to the opposite end point 19' of bar 8 and extends symmetrically with respect to wire 14 around the groove in the other roller 13 and has its free end fastened to a point 15' of the member 16. Fastening points 15 and 15' may coincide if desired.

In operation, a generally cylindrical work object 26, around the circumference of which a pattern is to be printed by means of the assembly described, is positioned upon a suitable base 27 so as to be freely rotatable thereon about its geometrical axis, by means of suitable needle bearings 28 or the like, so as to revolve about its said axis during the traverse of the screen 10 in engagement therewith, as will presently become apparent. Alternatively, means (not shown) may be provided for positively rotating the work 26 in synchronism with the traverse of the carriage 1 and screen 10. Both alternative arrangements just mentioned are well-known in the silk screen printing art and either may be used.

With the carriage 1 being reciprocated to and fro across the rails 2, 2 by any suitable traversing mechanism, not illustrated, it will be apparent that as the carriage 1 is traversed in the leftward direction according to FIG. 2, the roller 13 exerts a pull upon the wire 14 the end 15 of which is held stationary, and the wire transmits the pulling force to its opposite attaching point 19, thereby imparting to the bar 8 a leftward displacement. This constitutes a pre-se well-known flexible movement transmission system of the pulley-block variety, the kinematics of which is such that any displacement of the carriage 1 is transmitted to the arms 99' and hence to the silk screen 10, as a displacement substantially twice as great. At the end of the leftward traverse of the carriage 1, the arms 9 and 9 assume the positions indicated at 9a and 9a respectively. During this leftward traverse of the carriage and screen frame 10*, the squeegee carrier arm 17 remains stationary in a lowered or active position, in engagement with the screen which in turn is in engagement with the printing surface of the cylindrical work 26. As the carriage 1 and silk screen 10 reach the end of their respective leftward strokes, and preparatory to the reversal of the movement thereof, the links 21 and 22 are swung upwardly (according to FIG. 1) about their fixed pivots 23 and 24, so that the screen supporting arms 9, are lifted upwards to lift the screen 10 clear of the work surface, and the squeegee carrier arm 17 is lifted upwards correspondingly, both the frame 10 and arm 17 remaining horizontal owing to the geometry of the parallel linkage system described above. Thereupon the carriage 1 is displaced rightward, and at the end of this movement the screen supporting arms 9' and 9 assume the positions 912 and 9'b respectively. The links 21 and 22 are rotated clockwise about their pivots 23 and 24 to lower the silk screen 10 back into engagement with the work surface and simultaneously lower the squeegee carrier arm 17, and the apparatus is ready for a fresh printing cycle involving a leftward traverse of the carriage 1, in combination with the same work object 26 or a fresh one substituted therefor.

It will be understood that the actuating mechanism, not illustrated, serving to impart back-and-forth reciprocations to the carriage 1 and the synchronous up-anddown reciprocations to the links 21 and 22 may take up any appropriate form a wide variety of such mechanisms being well known and commercially available for use in the art.

Owing to the previously mentioned movement amplification by a factor of two, present between the displacements of carriage 1 and the corresponding displacements imparted to the frame carrying arms 9, 9 and silk screen 10, it will be apparent that the maximum stroke impartable to the silk screen 10, as determined between the opposite end positions, such as 3a and 9b, of either of the arms 9", is twice as great as the maximum stroke that would be impartable to said screen 10, were the screen supported directly from the carriage 1. Thus, a silk screen printing machine when equipped with the novel attachment described, will be capable of handling work articles having a developed circumferential extent twice as large as the articles which the machine is able to handle without said attachment.

FIGS. 3 and 4 illustrate a modified embodiment of the invention as applied to generally conical Work surfaces rather than the generally cylindrical surfaces for which the embodiment of FIGS. 1-2 is primarily intended. The assembly shown in FIGS. 3 and 4 has many parts in common with that of FIGS. 1-2 and its operating principle is essentially the same, so that corresponding parts are designated by the same references as those heretofore used and will not be again described in detail.

The main difference is that the straight reciprocating bar 8 of FIGS. 1 and 2 which serves to support the silk screen frame 10 by way of the arms 9, 9 is replaced, in the modification of FIGS. 3-4, by an arcuate bar 29. Projecting from symmetrical points of bar 29' is a pair of parallel spaced frame-supporting arms 30, 30 (corresponding to aforementioned arms 9, 9'), on which the frame 31 carrying the silk screen 32 proper, is positioned. The arcuate bar 29 is mounted for reciprocating sliding displacements along the circumference of which said arcuate bar forms a part, that is, for rotation in the genenal horizontal plane of the arcuate bar 29, about the virtual center 0 of the are, as will be clear from FIG. 4. The mounting means provided to that end comprise a pair of arms 33 and 33 supported rigidly at spaced positions upon the rail 2 and interconnected by a cross-member 34. Pivoted on vertical pivots or bolts 36, 36' at opposite ends of crossbar 34 are pairs of adjustable arms 35, 35' carrying end spigots 3'7, 37' having pairs of grooved rollers 38 and 38' rotatably mounted thereon in suitable bearings. The adjustable arms 35 and 35" can be angularly positioned through adjustment of their pivot bolts 36, 36' so that the axes of the rollers 38, 38' converge substantially towards the virtual center point 0, and it will therefore be evident that with the arcuate bar 29 slidably inserted between the pairs of grooved rollers 38 and 38 in a manner analogous to the insertion of bar 8 between the pairs of grooved rollers 7 in the embodiment of FIGS. 1-2, said arcuate bar 29 will be capable of being slidably reciprocated along its circumferential path as indicated above.

Such reciprocation is transmitted from the carriage 1 to the arcuate bar 29 through flexible elements or wires 14 and 14 in a manner closely similar to what was earlier described in connection with the first embodiment. That is, the wires 14 and 14' are herein attached at their one ends 19' and 19 to the opposite extremities of arcuate bar 29, and extend around grooved pulleys 13 and 13 supported at the ends of carriage 1, while the opposite ends of the wires are attached at 15 and 15 to a stationary part of the squeegee carrier assembly. It will be noted that in this embodiment each of the wires 14, 14' has an outer portion, near the attachment points 19 and 19" respectively, extending arcuately in engagement with the arcuate surface of the bar 29.

The operation of the embodiment of FIGS. 3 and 4 is very similar to what was earlier described, except that the silk screen 32 instead of being subjected to a rectilinear tnaversing reciprocation, is caused to describe a rotational movement about the point 0 as center. That is, the straight reciprocation of carriage 1 along rails 2, 2' is here converted through the flexible elements 14, 14' into an arcuate displacement of arcuate bar 29 about center 0, with the linear extent of the arcuate displacement of the bar, and hence screen 30', being twice as great as the linear extent of the corresponding displacement of carriage 1. In other words, assuming the original printing machine to which the embodiment of FIGS. 34 is applied, was capable of printing on conical work articles having a developed circumferential surface as indicated at efgh, when the silk screen frame 30 is supported directly from the reciprocating carriage 1, the machine constructed, or equipped with an attachment, in accordance With the invention as shown in FIGS. 3-4, will be capable of handling objects having a developed circumferential surface abcd twice as wide.

It will be evident that many modifications may be introduced into the exemplary constructions illustrated and described without exceeding the scope of the present invention. The various supporting structures and linkages used may differ considerably from those shown. While the invention appears to be of especial interest when embodied in an attachment constructed separately from, and fittable to, an existing silk-printing machine, it is also contemplated that the invention may be directly incorporated to such a machine.

While the systems shown herein by way of example provide for movement amplification by a factor of two, it will be clear that larger amplification factors might readily be obtained, by the simple use of pulley-block systems involving more than one pulley such as 13-13 per flexible element such as 14. That is, each such pulley may readily be replaced by two or more pulleys about which the related wire 14 or 1 4 is suitably passed, to provide a multiple pulley-block system capable of providing a movement transmission system with an amplification factor substantially greater than two. Embodiments of the invention utilizing such multiple pulley block systems are, therefore, to be expressly regarded as lying within the scope of the present invention.

What I claim is:

1. In a screen printing machine the improvement comprising (a) a stationary machine frame, supporting means for the screen frame, and a guide rail attached longitudinally sidewise to said supporting means,

(12) and driving means for said supporting means to reciprocate the same relative to the machine frame in a substantially horizontal plane including a driving carriage reciprocable in the machine frame; two pairs of cooperating gripping rollers mounted in spaced relation on said driving carriage and piloting said guide rail in its reciprocating movement; pulley means mounted at least near each side end of the driving carriage; two flexible tow-lines each embracing in mutually reversed and outwardly closed U- formation one of said pulley means by which each tow-line is divided into a first and a second horizontal branch, the end of each first branch being attached to a stationary part of the machine located substantially opposite the central portion of the guide rail in its central position, and the end of each second branch attached to the guide rail at least near that end thereof which lies on the same side of the machine fname as the guide pulley for the other towline, whereby said guide rail together with said supporting means is reciprocated at an increased rate and in directional agreement with the movement of the driving carriage.

2. A screen printing machine according to claim 1 for printing upon cylindrical surfiaces wherein said guide rail is rectilinear.

3. A screen printing machine according to claim 1 for printing upon conical surfaces wherein said guide rail is arcuately bent within said horizontal plane.

References Cited in the file of this patent UNITED STATES PATENTS 2,152,356 Meyer et al Mar. 28, 1939 2,444,174 Martin July 6, 1948 2,850,969 Ingersoll Sept. 9, 1958 2,972,943 Velonis Feb. 28, 1961 3,090,300 Dubuit May 21, 1963 

1. IN A SCREEN PRINTING MACHINE THE IMPROVEMENT COMPRISING (A) A STATIONARY MACHINE FRAME, SUPPORTING MEANS FOR THE SCREEN FRAME, AND A GUIDE RAIL ATTACHED LONGITUDINALLY SIDEWISE TO SAID SUPPORTING MEANS, (B) AND DRIVING MEANS FOR SAID SUPPORTING MEANS TO RECIPROCATE THE SAME RELATIVE TO THE MACHINE FRAME IN A SUBSTANTIALLY HORIZONTAL PLANE INCLUDING A DRIVING CARRIAGE RECIPROCABLE IN THE MACHINE FRAME; TWO PAIRS OF COOPERATING GRIPPING ROLLERS MOUNTED IN SPACED RELATION ON SAID DRIVING CARRIAGE AND PILOTING SAID GUIDE RAIL IN ITS RECIPROCATING MOVEMENT; PULLEY MEANS MOUNTED AT LEAST NEAR EACH SIDE END OF THE DRIVING CARRIAGE; TWO FLEXIBLE TOW-LINES EACH EMBRACING IN MUTUALLY REVERSED AND OUTWARDLY CLOSED UFORMATION ONE OF SAID PULLEY MEANS BY WHICH EACH TOW-LINE IS DIVIDED INTO A FIRST AND A SECOND HORIZONTAL BRANCH, THE END OF EACH FIRST BRANCH BEING ATTACHED TO A STATIONARY PART OF THE MACHINE LOCATED SUBSTANTIALLY OPPOSITE THE CENTRAL PORTION OF THE GUIDE RAIL IN ITS CENTRAL POSITION, AND THE END OF EACH SECOND BRANCH ATTACHED TO THE GUIDE RAIL AT LEAST NEAR THAT END THEREOF WHICH LIES ON THE SAME SIDE OF THE MACHINE FRAME AS THE GUIDE PULLEY FOR THE OTHER TOWLINE, WHEREBY SAID GUIDE RAIL TOGETHER WITH SAID SUPPORTING MEANS IS RECIPROCATED AT AN INCREASED RATE AND IN DIRECTIONAL AGREEMENT WITH THE MOVEMENT OF THE DRIVING CARRIAGE. 